1. Field
One or more embodiments relate to an optical detecting apparatus for a bio-chip.
2. Description of the Related Art
A bio-chip is a biopsy device similar to a semiconductor chip and may be formed by combining a biogenic organic compound, such as an enzyme, peptides, protein, antibody, or deoxyribonucleic acid (“DNA”) of a living organism, microorganism, cell, or organ, or a nerve cell of an animal or plant, onto a small chip. A DNA chip is a device for detecting DNA, which is made by arranging single-strand DNAs having different nucleotide base sequences, of which functions within a cell are known, within a small space on a substrate, such as on a glass substrate or a semiconductor substrate. A collection of single-strand DNAs having the same nucleotide base sequence is generally referred to as a spot, and generally 20 to 150 bases are connected to form one spot.
When genetic material of a sample flows on such a DNA chip, only genes corresponding to a specific spot, that is genes having a complementary nucleotide base sequence with a nucleotide base sequence of the specific spot, are combined with the corresponding spot, and genes which are not combined with spots in the DNA chip do not bind and may be washed out. Functions of nucleotide base sequences of spots arranged on a DNA chip are already known, and thus genetic information of a sample can be obtained by identifying spots in the DNA chip combined with genes. Therefore, aspects of unique genetic expression and/or alteration such as single nucleotide polymorphism and copy number variation in a gene or mutation in specific cells or organic tissues can be analyzed with relative rapidity. Furthermore, DNA chips can also be used in analysis of genetic expression, infection tests of pathogenic bacteria, antibiotic-resistance tests, research on biological reactions with respect to environmental factors, food safety inspection, identification of criminals, development of new drugs and medical inspection of animals or plants.
Various methods for identifying spots in a DNA chip combined with genes have been suggested, and the most popular method in this regard is the fluorescent detection method. In the fluorescent detection method, a base carrying a fluorescent material, which emits light of a specific color when excited by an excitation light, is combined with genetic material of a sample. After genetic material flows on a DNA chip, an excitation light is irradiated onto the DNA chip, and a fluorescent image obtained therein is analyzed. Thus, spots combined with genes of the sample can be identified. For example, the size of the spots ranges from 1 μm to 100 μm.
Generally, an optical detecting apparatus for obtaining a fluorescent image by irradiating excitation light onto a DNA chip obtains a fluorescent image by scanning a DNA chip in pixels of approximately 0.1 micrometers (“μm”) to 10 μm. Furthermore, hundreds to tens of millions of (e.g. 1,000) spots form an array in one DNA chip. Using a bio-chip scanner, that is a fluorescence detecting apparatus for reading an entire DNA chip by scanning each of spot arrays in the DNA chip, it takes a longer period of time to obtain a fluorescent image of higher resolution, and it generally takes approximately 10 minutes to read an entire DNA chip by scanning each of panels in the DNA chip. Furthermore, a longer period of time is necessary for converting a plurality of fluorescent images obtained from the scanning to information corresponding to original spots on the DNA chip.